16-cyano-7-oxopregnenolone and derivatives



United States Patent 16- CYAN 0-7 OXOPREGNENOLONE AND DERIVATIVESCharles W. Marshall, Skokie, and Robert H. Mazur, 'Evanston, Ill.,assignors to G. l). Searle & =Ce., (Ihicago, 111., a corporation ofIllinois N0 Drawing. Application August 22, 1955 Serial No. 529,907

.3 Claims. (Cl. 260-3974) This invention relates to16cyano-7-oxopregnenolone and derivatives, and processes for themanufacture thereof. More particularly, this invention relates tocompounds of the formula wherein Z is selected from the group consistingof CHGHrhydroxyethylene CHCH2 O-(f-lower alkyl lower alkanoyloxyethyleneCH=CH vinylene and o=onhydroxyvinylene radicals.

Vfhen Z in the generic formula above is hydroxyethylcue, the compoundrepresented is 16a-cyano-3 S-hydroxy pregn-5-ene-7,20-dione or, moreinformally, l6a-cyano-7- oxopregenolone. When Z in the formula is loweralkanoyloxyethylene, the designated compound is an ester of theaforesaid pregnenolone. When Z is the formula is a vinylene radical, thecompound specified is 16a-cyanopregna 3,5 diene 7,20 dione. Finally,when Z is hydroxyvinylene, the compound in question-is la-cyano-3-hydroxypregna-3,5-diene-7,20dione.

It will be recognized that the last named compoundabove.can anddoubtless does exist in several tautomeric forms. For example, it iswell known in chemistry that substances distinguished by the presence ofa hydroxyl radical attached to an ethylenic carbon atom as at C in theinstant structure are constitutionally disposed to participation inequilibrium mixtures with corresponding keto isomers, according to therelationship In the light of this prior art knowledge, it becomesevident that l6q-cyano-3hydroxypregna-3,5-diene-7,20-dione occurs notonly in the enolic configuration described, but is also found as thetrione.

Still further pertinent to the question of scope in the presentdisclosure is the prior art teaching that keto groups generally,regardless of position in a given molecule, tend to undergo at leasttransient enolization (that is to say, addition of a hydrogen ion and,in effect, shifting 20 of the ketonic double bond). It follows thatenolization of the subject steroids is presumably not reservedexclusively to the 3-position illustrated, but also involvesat least insome degree-the carbonyl at O, (for example), with or without shiftingof the C double bond. By this means, such structures as =0 CH: CN

H0 -or:

C=O CH:

lower alkyl-G-O 0H (5H3 0 CH:

and

are evolved. Of these, the 3-oxo-7-enol shares the dispositioncharacteristic of and described for its 7,3-isomer to participate inequilibria of the type thereby giving rise to the molecular arrangementThese latter tautomeric forms are thus seen to be, like the-ene-3,7,20-trio'ne discussed earlier, inherently contemplated in'the3-enolic and/or 7-oxo representation of the compounds of this inventionhereinelsewhere set forth; and in this respect, the assignment ofparticular structures and singular names to the substances of thepresent discovery is to be looked to, not for what is excluded, but

rather for that which is impliedthereby. Ultraviolet, in-

frared, and rotational data-clearly demonstrate that the claimed formofthe subject compounds is the predominating structure; but any and allofthe possible tauto- 4 be variously esterified, usingconventionaltechniquegto produce the claimed 3-alkanoates; or it may beoxidized by a kind of short-term Oppenauer procedure to give 16-cyano-2-hydroxy-pregna-3,S-diene-17,20-dioneof the invention. Inapreferred embodiment of the recommended Oppenauer modification, theoxidation is carried out using an aluminum alkoxide in toluene andcyclohexanone at temperatures of the order of 140-160 centrigrade forpe.-' riods of time ranging from minutes to not longer than 1 /2 hours;andthe reactionproduct is straight-way extracted intoa water-immisiciblesolvent, for example dichloromethane, which, in turn, is rapidly freedof aluminum salts by washing with, for example, dilute aqueous muriaticacid, thus insuring that the product is protected from the deteriorationwhich proceeds on appreciable contact with ketonic substances,particularly in the pres:

ence of such as the aforesaid aluminum salts.

The following examples describe in detail certain of the compoundsillustrative of the present invention and meththose skilled in the artof organic synthesis that many meric modifications thereof must, in thenature of such.

modifications, be considered equivalent for purposes of the presentinvention.

The compounds to which this. invention relates are valuable because oftheir pharmacological properties. Especially, the subject compounds areuseful by virtue of their selective anti-cortisone activity.Administered conjointly with cortisone, they inhibitthe sodium-excretingeffects of this medicament and correspondingly enhance itsmineralocorticoid function;

The compounds of the'present discovery are relatively insoluble inwater, but may be dissolved inethyl alcohol,

. isopropyl alcohol, acetone, benzene," chloroform, and other commonorganic solvents; The subject compounds .may be administered in solidform as tabletsor capsules;

dissolved or.suspended in aqueous media, they may be given parenterally.r 7' The claimed compounds are prepared in accordance with the followingprocedure: 3fl-acetoxypregna-5,16- 1 dien-ZO-one is converted tothelG-cyano derivative by interaction at elevated temperatures'in asolvent medium with hydrogen cyanide or a salt thereof--for example,potassiumcyanide. Treatment with pyridineand aceticanhydride insuresthat the resultant cyano compound is V This material is subjected'tochromate oxidation-preferablyiri glacial acetic acid 5 whollyacetoxylated at C medium-to give 3B-acetoxy-161x-cyanopregn-5-ene-7,20-'

i j dione, one of the compounds of the present invention.'De-acetoxylationwith, for example,- p-toluenesulfonic acid, yields the'claimed- '16wCyanoPregna-S,5-diene-7,20-'

dione of this invention, while'"alternativeIy-careful saponificationaffords the 3 hydroxy 5 ene 7,20- dione herein contemplatedl Thetlatter.compound may ads which have been devised for their manufacture. However,the invention is not to be construed as limited thereby, either inspirit or in scope, since it will be apparent to modifications, both ofmaterials and of methods, may be practiced without departing from thepurpose'and intent of this disclosure. In the examples hereinafterdetailed,

temperatures are givenin degrees centigrade .(C.) and a relative amountsof materials in parts by weight, except as otherwise noted. Specificrotations refer to the D line of sodium.

Examplel] 16a-cyan0-3fl-hydr0xypregrF5-en-20-Oiie. A suspension of 20parts of 3fi -acetoxypregna-5,16-dien-20-one and 20 parts of potassiumcyanide ina mixture "of 315 1 parts of methyl alcohol, 36 parts of ethylacetate, and 40 parts 'of water, is heated at reflux temperatures for 2hours." p A clear solution'results. introduction of S OOjp'arts ofwater, and cooling, causes precipitation of 160063 3110hydroxypregn-S-en-ZO-one, which is separated by filtration. The productis crystallized by dissolution in a mixture consisting of three volumesof methyl alcohol and 40 volumes of benzene,followed by concentration ofthe resultantsolution to approximately 25 volumes. The cyano steroidcomes down as clustered needles, M. P. 225-228? C., specific rotation+23 in methyl alcohol at room temperatures. Ithas the formula Example :2

12 'parts of 16a-cyano-3fl-hydroxypregn-5-ene12Q-one '.;in

180 parts of pyridine and parts of aceticanhydrideiis I allowed to standat room temperatures overnightgfollow ing which excess anhydride'isdecomposed by additioii of j water with cooling and stirring; Thereaction mixture is M. P. '18919 Z C. 1

Example 3 3'18-acetoxy-I6u cyanbpregn-5-ene-7,ZO-dioneQ -}-To an 7'oxidizing mixture prepared by adding 11 parts" of chro- T 5 miumtrioxide and 30 parts of anhydrous potassium carbonate to 150 parts ofacetic acid and 90 parts of acetic anhydride is added a solution of 24parts Of the product of the preceding Example 2 in 240 parts of a 1:1mixture of acetic acid and acetic anhydride. The reactants are allowedto stand for 48 hours at room temperature with agitation, followingwhich they are cooled in an ice bath while excess anhydride isdecomposed by addition of Water. The reaction mixture is then extractedwith chloro form and the chloroform solution so obtained washed 3 timeswith water. Dried over anhydrous sodium sulfate, the solution is freedof solvent by distillation; and the residue is chromatographed on 20parts by weight of silica gel, using 10% ethyl acetate'in benzeneasdeyeloping solvent. There is thus obtained, purified 3fi-acetoxy-16a-cyanopregn-5-ene-7,20-dione which, crystallized from a mixture ofbenzeneand cyclohexane, shows M. P. approximately 206.4 -2 07.4 f C. Theproduct displays a specific rotation of 70 in methyl alcohol solution atroom temperatures. It has the formula HsCC-O 0 Example 416a-cyanopregna-3,5-diene-7,20-diane.A solution of 2 parts of3,8-acetoxy-l6a-cyanopregn-5-ene-7,20-dione and 2 parts ofp-toluenesulfonic acid monohydrate in 100 parts of glacial acetic acidcontaining 3 parts of acetic anhydride is heated at reflux temperaturesfor 1 /2 hours. Excess anhydride is then destroyed by addition of waterto the ice-cold solution, following which the reactants are extractedwith chloroform. The chloroform extract is washed with water andsaturated aqueous sodium bicarbonate, respectively, and dried overanhydrous sodium sulfate, in that order. Chloroform is removed bydistillation, and the residue thereupon chromatographed on 20 parts ofsilica gel, using ethyl acetate in benzene as developing solvent. Thepurified l6a-cyanopregna-3,5- diene-7,20-dione thus obtainedcrystallizes from benzene in dumbbell shaped clusters of needles, M. P.approximately 237.2-238 C., specific rotation -321 in methyl alcohol atroom temperatures. The product has the formula Example 516wcyano-SB-hydroxypregn-S-ene-7,20-di0ne. To a solution of 6 parts of3,3-acetoxy-16a-cyauopregn-5-ene- 7,20-dione in 206 parts of purifieddioxan is added, with agitation, 5 parts of potassium hydroxidedissolved in 140 parts of water. The reaction mixture, cloudy at first,becomes clear as the water content exceeds approximately 30%. Thereactants are maintained for 90 minutes at 6 room temperatures in aninert atmosphere, following which they are combined with 4000 parts ofwater containing 5 parts of muriatic acid and parts of sodium chloride.The precipitate which forms is extracted into 2 500-part quantities ofethyl acetate. The extracts are combined, washed 3 times with 5% aqueoussodium chloride and finally with saturated aqueous sodium chloride,dried over anhydrous sodium sulfate, and filtered, in that order. Thefiltrate is distilled in vacuo to approximately ,4 the original volume,following which a first crop of the desired16a-cyano-3fl-hydroxypregn-S-ene- 7,20-dione precipitates on standing.Further concentration of the mother liquors affords additional product.Upon recrystallization from ethyl acetate, the pure product is obtainedin the form of slender prisms, M. P. 209-210 C. The material shows aspecific rotation of 95 in chloroform solution at room temperatures, andis characterized by an ultraviolet peak at 237.5 millimicrons, with amolecular extinction coefficient of 13,500. The infrared spectrumreveals characteristic bands at 2.88, 5.88, 6.05, and 6.17 microns. Theproduct has the formula Example 6 16u-cyano-3-hydroxypregna 3,5diene-7,20-dione. A solution of 16 parts of16a-cyano-3fi-hydroxypregn-5- ene-7,20-dione in 1300 parts of drytoluene is azeotropically distilled under a nitrogen atmosphere to /5its original volume, thus removing any residual moisture present. Tothis solution at 160 C. is then added parts of cyclohexanone, followedover a 5 minute period by 30 parts of aluminum isopropoxide dissolved in130 parts of dry toluene. Heating at is continued for an additional 25minutes, anhydrous conditions being main tained by continuous slowdistillation during this time whereby approximately parts of toluene isremoved. The reaction mixture is next cooled to approximately 5 C. andmixed well with 6700 parts of cold dichloromethane and 4000 parts ofwater in which is dissolved 150 parts of sulfuric acid and 200 parts ofsodium chloride. The aqueous phase is separated, reextracted with 1350parts of dichloromethane, and finally discarded. The organic solventsolutions are combined and washed with 2000 parts of water containing 75parts ,of sulfuric acid and 100 parts of dissolved sodium chloride,following which they are thrice rapidly extracted with 1500-partportions of cold water, each such portion containing 30 parts of causticsoda dissolved therein. The alkaline extracts-immediately asindividually obtained-are poured into an excess of cold 5% aqueousmuriatic acid containing 3%sodium chloride. The material thusprecipitated is extracted with 6700 parts and 2000 parts, respectively,of dichloromethane. These extracts are combined and washed 3 times with5% aqueous sodium chloride. The washed solution is then dried overanhydrous sodium sulfate and filtered. The filtrate is evaporated todryness in vacuo under an atmosphere of nitrogen, leaving as a residue alight yellow resin which crystallizes from acetone as small prisms, M.P. l75-l77 C. The product thus obtained,16a-cyano-3-hydroxy-pregna-3,5-diene-7,20-dioue,

Q is distinguished by an ultraviplet spectrnm (0.0011% in methylalcohol) wherein there is a major peak typical of r r r 2,324,882 r 1 sWha t'is claimed is: V l l 1. A compdundof'the formulaA-hydroxy-a,'y-dienones at 321 millimicrons; with a r V I ,v 'mo'lecularextinctioncoeflicient of 21,700. The infrared 7 f 7 spectrum'rnanifests'principal absorption bands at 3.16,- 5 1 I V V I 4.45, 5.88, 6.28, and6.45 microns. The'product is repre- V '7 I v r H, 7 sented byrthe enolicformula '7 i I r r j Y OH: 7 1 V 10 'droxy and lower alkanoyloxyradicals. V

2. 3B-acetoxy-16a-cyanopregn-5-ene-7,20 dione.

16a-cyano-3fi-liydrdxypregn-S-en-ZZO-diohe;'

H0 No references cited;

wherein R is selected from the group consisting of hy- U. 5. DEPARTMENTOF COMMERCE PATENT OFFICE CERTIFICATE OF CQRRECTION Patent No, 2,824,882February 25, 1958 Charles Wa Marshall et ale It is hereby certified thaterror appears in the printed specification of the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 2, line 2, after the Word "trione" strike out the periodfi column4, line 4, for "oyano-2-11ydroxy-=pregna=3,5==diene =l'7,2O-=di0ne" readoyano=3=hydroxypregna=3,5==diene-=7,20dione line 8, for oezrltrigrade"read n centigrade line '71, for "pregn-=5-ene 20-= one; readpregn=5=en=20==one, column 5, line 6, for "temperature read temperaturesSigned and sealed this 29th day of April 1958.,

(SEAL) Attest:

KARL AXLINE ROBERT C. WATSON Atteeting Officer Commissioner of Patents

1. A COMPOUND OF THE FORMULA